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Very little current [DRV8837]

Jose Mingorance
Prodigy 10 points
Other Parts Discussed in Thread: DRV8837

Hi everyone!

I have two questions about the low-voltage h-bridge ic DRV8837:

-On page number 7 of the DRV8837 datasheet there is
an unclear information. What does it mean "very little
current from VM"? The amount of current is critical for
my device and I would like to know some parameters
in order to determine the right meaning of "very little".

-It is also really important for me to know what does the
OCP inside have, in order to know if it is possible to have a
voltage drop between VM and OUT1 (or OUT2) apart
from the 280 mOhm of the MOSFET On-Resistance.

Yours faithfully,
Jose

  • 0
    TI__Guru 55615 points

    Jose,

    Sorry for the uncertain statement.

    The current when VCC is removed is the same as the I(vmq) number in the tabular data which is the VM sleep-mode supply current.  When VCC is removed, the device automatically enters the sleep state and the current is nominally 30nA and max. of 95nA as the table implies.

    The OCP circuit is not "in-line" with the output FET as shown in the block diagram.  It is essentially a current mirror that scales the current in the output FETs.  This scaled current is compared to an on-chip reference to set the OCP trip point.  So, you do not need to consider this in the voltage drop calculations.